What is the difference between a good conductor and a poor conductor? Give two example of each.

Define the electric resistance of a wire and also write its SI unit.

Keeping the potential difference constant, the resistance of a circuit is halved. Then, how much does the current changes?

The potential difference across wire is 75V and its electric resistance is 30Ω. Find out the electric current through the wire.

If the length of a wire is halved and its cross-sectional area is doubled, then what would be the resistance of the wire?

(Given, initially the resistance of the wire is R)